The invention relates to nitrogen-containing heterocyclic compounds, to their preparation and to their use as antibacterial drugs.
The application WO 04/052891 notably describes compounds fitting the following formula:
wherein:R1 represents a hydrogen atom, a COOH, COOR, CN, (CH2)n′R5, CONR6R7 or radical
R is selected from the group formed by an alkyl radical containing 1 to 6 carbon atoms, optionally substituted with one or more halogen atoms or with a pyridyl radical, a —CH2-alkenyl radical containing a total of 3 to 9 carbon atoms, a (poly)alkoxyalkyl group containing 1 to 4 oxygen atoms and 3 to 10 carbon atoms, an aryl radical containing 6 to 10 carbon atoms or an aralkyl radical containing 7 to 11 carbon atoms, the ring of the aryl or aralkyl radical being optionally substituted with an OH, NH2, NO2, alkyl radical containing 1 to 6 carbon atoms, an alkoxy radical containing 1 to 6 carbon atoms or with one or more halogen atoms,R5 is selected from the group formed by a COOH, CN, OH, NH2, CO—NR6R7, COOR, OR radical, R being defined as above,R6 and R7 are individually selected from the group formed by a hydrogen atom, an alkyl radical containing 1 to 6 carbon atoms, an alkoxy radical containing 1 to 6 carbon atoms, an aryl radical containing 6 to 10 carbon atoms and an aralkyl radical containing 7 to 11 carbon atoms and an alkyl radical containing 1 to 6 carbon atoms substituted with a pyridyl radical,n′ is equal to 1 or 2,R3 and R4 form together a phenyl or a heterocycle with aromaticity with 5 or 6 apices containing 1 to 4 heteroatoms selected from nitrogen, oxygen and sulfur, substituted with one or more R′ groups, R′ being selected from the group formed by the —(O)a—(CH2)b—(O)a—CONR6R7, —(O)a—(CH2)b—OSO3H, —(O)a—(CH2)b—SO3H, —(O)a—SO2R, —(O)n—SO2—CHal3, —(O)a—(CH2)bNR6R7, —(O)a—(CH2)b—NH—COOR, —(CH2)b—COOH, —(CH2)b—COOR, —OR″, OH, —(CH2)b— phenyl radicals and (CH2)b-heterocycle with aromaticity with 5 or 6 apices containing 1 to 4 heteroatoms selected from nitrogen, oxygen and sulfur, the phenyl and the heterocycle being optionally substituted with one or more halogens, an alkyl containing 1 to 6 carbon atoms, an alkoxy containing 1 to 6 carbon atoms or CF3, R, R6 and R7 being as defined earlier, R″ being selected from the group formed by alkyl radicals containing 1 to 6 carbon atoms substituted with one or more hydroxy, protected hydroxy, oxo, halogen or cyano radicals, a being equal to 0 or 1 and b being an integer from 0 to 6, it being understood that when R′ is OH, R1 represents the radical CONR6R7 wherein R6 or R7 is an alkoxy containing 1 to 6 carbon atoms,R2 is selected from the group formed by a hydrogen atom, a halogen atom and R, S(O)mR, OR, NHCOR, NHCOOR and NHSO2R radicals, R being as defined earlier and m being equal to 0, 1 or 2,X represents a divalent group —C(O)—B— linked to the nitrogen atom through the carbon atom,B represents a divalent group —O—(CH2)n″— linked to the carbonyl through the oxygen atom, a group —NR8—(CH2)n″— or —NR8—O— linked to the carbonyl through the nitrogen atom, n″ is equal to 0 or 1 and R8 is selected from the group formed by a hydrogen atom, an OH, R, OR, Y, OY, Y1, OY1, Y2, OY2, Y3, O—CH2—CH2—S(O)m—R, SiRaRbRc and OSiRaRbRc radical, Ra, Rb and Rc individually representing a linear or branched alkyl radical containing 1 to 6 carbon atoms or an aryl radical containing 6 to 10 carbon atoms, and R and m being defined as earlier,Y is selected from the group formed by the COH, COR, COOR, CONH2, CONHR, CONHOH, CONHSO2R, CH2COOH, CH2COOR, CHF—COON, CHF—COOR, CF2-COOH, CF2-COOR, CN, CH2CN, CH2CONHOH, CH2CONHCN, CH2-tetrazole, CH2-(protected tetrazole), CH2SO3H, CH2SO2R, CH2PO(OR)2, CH2PO(OR)(OH), CH2PO(R)(OH) and CH2PO(OH)2 radicals,Y1 is selected from the group formed by the SO2R, SO2NHCOH, SO2NHCOR. SO2NHCOOR, SO2NHCONHR, SO2NHCONH2 and SO3H radicals,Y2 is selected from the group formed by the PO(OH)2, PO(OR)2, PO(OH)(OR) and PO(OH)(R) radicals,Y3 is selected from the group formed by the radicals, tetrazole, tetrazole substituted with the radical R, squarate, NH or NR tetrazole, NH or NR tetrazole substituted with the radical R, NHSO2R and NRSO2R, CH2-tetrazole and CH2-tetrazole substituted with R, R being defined as above, andn is equal to 1 or 2,as well as the salts of these compounds with mineral or organic bases or acids.
The asymmetrical carbon atoms contained in the compounds of formula (I) may independently of each other have the R, S or RS configuration and the compounds of formula (I) therefore appear as pure enantiomers or pure diastereoisomers or as a mixture of enantiomers, notably of racemates, or mixtures of diastereoisomers. Further, the substituent R1, R2, or R4 taken individually on the one hand and X on the other hand may be in the cis and/or trans position relatively to the ring on which they are attached, the compounds of formula (I) appear as cis isomers or trans isomers or mixtures thereof. Moreover, the application WO 02/100860 describes related compounds. The applicant has discovered that among the compounds described in the application WO 04/052891, certain particular compounds, none of which are described in the experimental part of this application, have quite unexpected antibacterial properties.
The unique character of the compounds of the invention lies in the fact that they have excellent activity on Pseudomonas aeruginosa, a bacterial strain frequently encountered in nocosomial infections as well as in patients suffering from cystic fibrosis. This interesting and unexpected activity is not present in compounds closest to them as prepared in the application WO 04/052891. It is illustrated later on in the experimental part.
Moreover, the compounds of the invention proved to be active on animal infection models, including on strains usually resistant to commonly used antibiotics. The compounds of the invention are capable of thwarting the main mechanisms of bacterial resistance which are β-lactamases, efflux pumps and mutations of porins.
The compounds of the invention are compounds fitting the formula above wherein R2 represents a hydrogen atom, X represents a divalent group C(O)NR8 wherein R8 is a OY1 radical, Y1 being a SO3H radical, and especially including the following particular combination of substituents R1, R3, R4:
R1 represents an alkyl radical substituted with an amino radical and R3 and R4 form together a nitrogen-containing heterocycle with aromaticity with 5 apices substituted with a group including or consisting in a polar substituent of the amino or aminated aromatic heterocycle or carboxy type.
The object of the invention is thus the compounds of general formula (I), in their possible isomer or diastereoisomer forms or mixtures:
wherein:R1 represents a (CH2)n—NH2 radical, n being equal to 1 or 2;R2 represents an hydrogen atom;R3 and R4 form together a nitrogen-containing heterocycle with aromaticity with 5 apices containing 1, 2 or 3 nitrogen atoms, substituted on this nitrogen atom or on one of these nitrogen atoms with a (CH2)m—(C(O))p—R6 group, m being equal to 0, 1, 2 or 3, p being equal to 0 or 1 and R5 representing a hydroxy group, in which case p is equal to 1, or an amino, (C1-C6)alkyl or di-(C1-C6)alkyl amino group, or a nitrogen-containing heterocycle with aromaticity with 5 or 6 apices containing 1 or 2 nitrogen atoms, and, if necessary, an oxygen or sulphur atom; it being understood that when the sub-group (C(O))p—R6 forms a carboxy, amino or (C1-C6)alkyl or di-(C1-C6)alkyl amino group, m is different from 0 or 1; in free form and as zwitterions and salts with pharmaceutically acceptable mineral or organic bases and acids.
By alkyl radical containing 1 to 6 carbon atoms, is notably meant the methyl, ethyl, propyl, isopropyl radical, as well as a linear or branched butyl, pentyl or hexyl radical. By heterocycle with aromaticity with 5 apices containing 1, 2 or 3 nitrogen atoms, are meant those selected in the following list, the two bonds symbolizing the junction with the nitrogen-containing ring formed by R3 and R4:

By nitrogen-containing heterocycle with aromaticity with 5 or 6 apices containing 1 or 2 nitrogen atoms and if necessary 1 oxygen or sulfur atom, are meant those of the type illustrated above, or an oxazole or thiazole ring, or a ring with 6 apices of the pyridine, pyrazine, pyrimidine or pyridazine type, the heterocycle being attached to the chain or to the heterocycle formed by R3 and R4 through a nitrogen atom or a carbon atom. Among the acid salts of the products of formula (I), mention may i.a. be made of those formed with mineral acids such as hydrochloric, hydrobromic, hydroiodic, sulfuric or phosphoric acids or with organic acids such as formic, acetic, trifluoroacetic, propionic, benzoic, maleic, fumaric, succinic, tartaric, citric, oxalic, glyoxylic, aspartic, alkane-sulfonic acids, such as methane- and ethane-sulfonic acids, arylsulfonic acids such as benzene- and paratoluene-sulfonic acids. Among the salts of the products of formula (I), mention may be made, i.a., of those formed with mineral bases such as for example, sodium, potassium, lithium, calcium, magnesium or ammonium hydroxide or with organic bases such as for example methylamine, propylamine, trimethylamine, diethylamine, triethylamine, N,N-dimethylethanolamine, tris(hydroxymethyl)aminomethane, ethanolamine, pyridine, picoline, dicyclohexylamine, morpholine, benzylamine, procaine, lysine, arginine, histidine, N-methylglucamine, or further phosphonium salts such as alkylphosphoniums, arylphosphoniums, alkylarylphosphoniums, alkenylaryl-phosphoniums, or quaternary ammonium salts such as tetra-n-butylammonium salts.
The asymmetrical carbon atoms contained in the compounds of formula (I) may independently of each other have the R, S or RS configuration and the compounds of formula (I) therefore exist as pure enantiomers or pure diastereoisomers or as a mixture of enantiomers, notably of racemates or mixtures of diastereoisomers. Further, the substituent R1 on the one hand and the chain —C(O)—N(OSO3H)— on the other hand may be in the cis and/or trans position relatively to the ring on which they are attached, the compounds of formula (I) exist as cis isomers or trans isomers or mixtures.
Among the compounds of formula (I), the object of the invention is notably the compounds wherein R3 and R4 form together a substituted pyrazolyl heterocycle. Among the compounds of formula (I), the object of the invention is notably those wherein R1 is a (CH2)n—NH2 group, n being equal to 1 and the heterocycle formed by R3 and R4 is substituted with a (CH2)m—(C(O))p—R5 group as defined earlier, and more particularly among the latter, those wherein R5 represents an amino, (C1-C6)alkyl or di-(C1-C6)alkyl amino, m and p being as defined earlier.
Among the compounds of formula (I), the object of the invention is most particularly the compounds described later on in the experimental part and notably those of the following names:    trans 8-(aminomethyl)-2-carbamoyle-4,8-dihydro-5-(sulfo-oxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-2-dimethylcarbamoyle-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-2-methylcarbamoyle-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-1-(2-aminoethyl)-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-2-(2-aminoethyl)-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)—O-one,    trans 8-(aminomethyl)-2-(2-pyridinyl)-4,8-dihydro-5-(sulfo-oxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans [[8-(aminomethyl)-5,6-dihydro-6-oxo-5-(sulfooxy)-4H-4,7-methanopyrazolo[3,4-e][1,3]diazepin-2(8H)-acetic acid, trans    8-(aminomethyl)-5,6-dihydro-6-oxo-5-(sulfooxy)-4H-4,7-methanopyrazolo[3,4-e][1,3]diazepin-2(8H)-acetamide,in free form, as zwitterions and salt with pharmaceutically acceptable mineral or organic bases and acids, and as possible isomers or diastereoisomers, or mixtures.
Another object of the invention is a method for preparing compounds of formula (I), characterized in that a compound of formula (II) is treated:
wherein represents an R′1 radical wherein the nitrogen atom is protected, R2 is as defined above, R′3 and R′4 form together a nitrogen-containing heterocycle with aromaticity with 5 apices containing 1, 2 or 3 nitrogen atoms and P represents a group protecting the hydroxy radical, in the presence of a base, with a compound of formula (III):X—(CH2)m—(C(O))p—R′5  (III)wherein X represents a halogen atom or an OH group which may be activated, m and p are as defined above and R′5 represents an R5 radical wherein the reactive amino or carboxy group is, if necessary, protected, in order to obtain a compound of formula (IV):
wherein R′1, R2 and P are as defined above and R″3 and R″4 form together a nitrogen-containing heterocycle with aromaticity with 5 apices as defined above for R3 and R4, substituted with a (CH2)m—(C(O))p—R′5 group, m, p and R′5 being as defined above,and the hydroxyl radical is then deprotected and the obtained compound is submitted to a sulfatation reaction by action of complexed SO3, and then, if necessary the obtained compound is submitted to one or more of the following reactions, in a suitable order:
deprotection of the present aminated function(s) and if necessary of the carboxy group,
salification,
ion exchange,
resolution or separation of diastereoisomers.
Preliminary protection of the amine at R′1, and R′5 is notably carried out in the form of benzylated or tritylated derivatives, of carbamates, notably allyl, benzyl, phenyl or tertbutyl carbamates, or further in the form of silylated derivatives such as tertbutyl dimethyl, trimethyl, triphenyl or further diphenyltertbutyl-silyl derivatives, or further phenylsulfonylalkyl or cyanoalkyl derivatives. Deprotection may be carried out with different methods known to one skilled in the art, depending on the nature of the protective group. It may notably be carried out through the action of an acid, for example trifluoroacetic acid, the deprotected compound being then obtained as a salt of the acid. It may further be carried out by hydrogenolysis or with soluble complexes of palladium(0) or through the action of tetrabutylammonium fluoride or by reduction. An illustration is provided further on in the experimental part.
The preliminary protection of the carboxy at R′5 is notably carried out in the form of derivatives of the ester type, notably alkyl, allyl, benzyl, benzhydryl or p-nitro benzyl esters. Deprotection may be carried out with different methods known to one skilled in the art, for example by saponification, acid hydrolysis, hydrogenolysis or cleavage with soluble complexes of palladium(0). The base in the presence of which the compound of formulae (II) and (III) are reacted may for example be an alkaline carbonate but other bases known to one skilled in the art may be used.
The preliminary protection of the hydroxyl of the compound of formula (II) is carried out in a standard way, in the form of ethers, esters or carbonates. The ethers may be alkyl or alkoxyalkyl ethers, preferably methyl or methoxyethoxmethyl ethers, aryl ethers, or preferably aralkyl ethers, for example benzyl ethers, or silylated ethers, for example the silylated derivatives mentioned above. The esters may be any cleavable ester known to one skilled in the art and preferably an acetate, propionate or benzoate or p-nitrobenzoate. The carbonates may for example be methyl, tertbutyl, allyl, benzyl or p-nitrobenzyl carbonates.
Deprotection is carried out with means known to one skilled in the art, notably saponification, hydrogenolysis, cleavage by soluble complexes of palladium(0), hydrolysis in an acid medium or further, for silylated derivatives treatment with tetrabutylammonium chloride, an illustration is provided further on in the experimental part. The possible activation of the hydroxyl of the compound of formula (III) is achieved in the form of a mesylate or tosylate, under conditions known to one skilled in the art. The sulfatation reaction is carried out by action of SO3 complexes such as SO3-pyridine or SO3-dimethylformamide, by operating in pyridine or in dimethylformamide, the salt formed, for example the salt of pyridine, may be exchanged for example with a salt from another amine, a quaternary ammonium or an alkaline metal. An illustration is provided in the experimental part.
Salification by acids is if necessary carried out by adding an acid in a soluble phase to the compound. Salification by bases of the sulfo-oxy function may be achieved from the amine salt, and notably pyridine salt obtained during the action of the SO3-amine complex and the other salts are obtained from this amine salt. It is notably possible to operate with ion exchange on a resin. The separation of the enantiomers and diastereoisomers may be achieved according to techniques known to one skilled in the art, notably chromatography either on a chiral phase or not. Examples of conditions which may be used are also described in application WO 04/052891 or further application WO 02/100860.
The compounds of formula (I) wherein n is equal to 0, p is equal to 1 and R5 represents R″5, R″5 representing an amino, (C1-C6) alkyl or di-(C1-C6)alkyl amino, may further be obtained by a method characterized in that a compound of formula (II) as defined above is treated in the presence of a base, with diphosgene and then with an amine of formulaH—R″5 wherein R″5 has the values of R5 above, in order to obtain a compound of formula (IV′):
wherein R′1, R2 and P are as defined above and R3 and R4 form together a nitrogen-containing heterocycle with aromaticity with 5 apices as defined above, substituted with a —C(O)—R″5 group, R″5 being as defined above, and the synthesis is then continued as described above in the case of the compound of formula (IV).
The base used during the action of diphosgene may notably be a tertiary amine such as triethylamine. These same compounds of formula (I) may further if necessary be obtained with a method characterized in that a compound of formula (II) as defined above is treated with trimethylsilyl isocyanate or with an isocyanate of formula(C1-C6)alkyl-N═C═OIn order to obtain a corresponding compound of formula (IV), the synthesis is then continued as described above. The compounds of formula (I) wherein R5 represents a heterocycle may be obtained with different reactions known to one skilled in the art for forming C—N bonds and notably by catalysis with palladium or copper as the one described in one of the examples hereafter.
As indicated above, the compounds of general formula (I) have excellent antibiotic activity on Pseudomonas aeruginosa as well as on animal infection models by strains resistant to commonly used antibacterial agents. This remarkable and unexpected antibiotic activity had not been observed for the compounds described in application WO 04/052891 and notably for the compounds structurally close to them. This is illustrated later on. These properties make said compounds suitable in the free form or as zwitterions or salts of pharmaceutically acceptable acids and bases, for use as drugs in treating severe infections by Pseudomonas, notably nosocomial infections and, generally, major infections in subjects at risks. These may in particular be infections of the respiratory tracts, for example acute pneumonia or chronic infections of the lower tracts, blood infections for example septicemias, acute or chronic infections of the urinary tracts, those of the auditory system, for example malign external otitis, or suppurating chronic otitis, those of the skin and of soft tissues, for example dermatitises, infected wounds, folliculitis, pyodermatis, stubborn forms of acne, eye infections, for example corneal ulcer, those of the nervous system, notably meningitises and brain abscesses, heart infections such as endocarditis, infections of bones and joints, such as stenoarticular pyoarthrosis, vertebral osteomyelitis, pubic symphysitis, infections of the gastro-intestinal tract, such as necrosing enterocolitis and perirectal infections.
Therefore the object of the present invention also is, in the form of drugs, and notably as antibiotic drugs, the compounds of formula (I) as defined above, in free form and as zwitterions and salts with pharmaceutically acceptable mineral or organic bases and acids. Among the compounds of formula (I), the object of the invention is notably the compounds, as drugs, wherein R3 and R4 form together a substituted pyrazolyl heterocycle. Among of the compounds of formula (I), the object of the invention is more particularly the compounds as drugs, wherein R1 is a (CH2)n—NH2 group, n being equal to 1 and the heterocycle formed by R3 and R4 is substituted with a (CH2)m—(C(O))p—R5 group as defined earlier, and more particularly among the latter, those in which R5 represents an amino, (C1-C6)alkyl or di-(C1-C6)alkyl amino group, m and p being as defined earlier.
Among the compounds of formula (I), the object of the invention is most particularly the compounds, as a drug, with the following names:    trans 8-(aminomethyl)-2-carbamoyle-4,8-dihydro-5-(sulfo-oxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-2-dimethylcarbamoyle-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-2-methylcarbamoyle-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-1-(2-aminoethyl)-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-2-(2-aminoethyl)-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans 8-(aminomethyl)-2-(2-pyridinyl)-4,8-dihydro-5-(sulfooxy)-4,7-methano-7H-pyrazolo[3,4-e][1,3]diazepin-6(5H)-one,    trans [[8-(aminomethyl)-5,6-dihydro-6-oxo-5-(sulfooxy)-4H-4,7-methanopyrazolo[3,4-e][1,3]diazepin-2(8H)-acetic acid,    trans 8-(aminomethyl)-5,6-dihydro-6-oxo-5-(sulfooxy)-4H-4,7-methanopyrazolo[3,4-e][1,3]diazepin-2(8H)-acetamide,in free form, as zwitterions and salts with pharmaceutically acceptable mineral or organic bases and acids, and in their possible isomer or diastereoisomer forms, or mixtures.
The object of the invention is also pharmaceutical compositions containing as an active ingredient, at least one of the compounds according to the invention as described above. These compositions may be administrated via a buccal, rectal, parenteral, notably intramuscular route, or via a local route, by topical application on the skin and mucosas. The compositions according to the invention may be solid or liquid and exist as pharmaceutical forms currently used in human medicine such as for example simple or sugar-coated tablets, gelatin capsules, granules, suppositories, injectable preparations, ointments, creams, gels; they are prepared according to the usual methods. The active ingredient(s) may be incorporated to excipients usually used in these pharmaceutical compositions, such as talc, gum arabic, lactose, starch, magnesium stearate, cocoa butter, aqueous carriers or not, fats of animal or plant origin, paraffinic derivatives, glycols, various wetting agents, dispersants or emulsifiers, preservatives. These compositions may notably exist as a lyophilisate intended to be dissolved extemporaneously in a suitable carrier, for example, apyrogenic sterile water.
The administered dose is variable depending on the treated disease, the subject in question, the administration route, and the relevant product. It may for example be comprised between 0.250 g and 10 g daily, orally in humans, with the product described in Examples 1, 4 or 5 or further comprised between 0.25 g and 10 g daily via an intramuscular or intravenous route. The products of formula (I) may also be used as disinfectants of surgical instruments.